Again, homosexuality is not a choice

New research strongly suggests that if human sexuality isn't determined before birth, then at least it happens shortly after. That is, way before any "lifestyle" choices can be made.

A group of 90 healthy gay and heterosexual adults, men and women, were scanned by the Karolinska Institute scientists to measure the volume of both sides, or hemispheres, of their brain.

When these results were collected, it was found that lesbians and heterosexual men shared a particular "asymmetry" in their hemisphere size, while heterosexual women and gay men had no difference between the size of the different halves of their brain.

In other words, structurally, at least, the brains of gay men were more like heterosexual women, and gay women more like heterosexual men.

A further experiment found that in one particular area of the brain, the amygdala, there were other significant differences.In heterosexual men and gay women, there were more nerve "connections" in the right side of the amygdala, compared with the left.

The reverse, with more neural connections in the left amygdala, was the case in homosexual men and heterosexual women.

Homosexuality is not a choice. But we already knew that, because no one can say that they chose to be heterosexual at some age.

But, even if it was a choice, that would be their choice.

Oh, and, see this post by someone who knows statistics well, and found that something was amiss with the original paper.

Pleiotropy comes from the Greek πλείων pleion, meaning "more", and τρέπειν trepein, meaning "to turn, to convert". It designates the occurrence of a single gene affecting multiple traits, and is a hugely important concept in evolutionary biology.

I'm a postdoc at UC Santa Barbara.

All Many aspects of evolution interest me, but my research focus is currently on microbial evolution, adaptive radiation, speciation, fitness landscapes, epistasis, and the influence of genetic architecture on adaptation and speciation.